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<font color='#009900'>// Copyright (C) 2010  Davis E. King (davis@dlib.net)
</font><font color='#009900'>// License: Boost Software License   See LICENSE.txt for the full license.
</font><font color='#0000FF'>#undef</font> DLIB_AnY_ABSTRACT_H_
<font color='#0000FF'>#ifdef</font> DLIB_AnY_ABSTRACT_H_

<font color='#0000FF'>#include</font> <font color='#5555FF'>&lt;</font>typeinfo<font color='#5555FF'>&gt;</font>

<font color='#0000FF'>namespace</font> dlib
<b>{</b>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>class</font> <b><a name='bad_any_cast'></a>bad_any_cast</b> : <font color='#0000FF'>public</font> std::bad_cast 
    <b>{</b>
        <font color='#009900'>/*!
            WHAT THIS OBJECT REPRESENTS
                This object is the exception class used by the any object.
                It is used to indicate when someone attempts to cast an any
                object into a type which isn't contained in the any object.
        !*/</font>

    <font color='#0000FF'>public</font>:
          <font color='#0000FF'>virtual</font> <font color='#0000FF'>const</font> <font color='#0000FF'><u>char</u></font><font color='#5555FF'>*</font> <b><a name='what'></a>what</b><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font color='#0000FF'>const</font> <font color='#0000FF'>throw</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <b>{</b> <font color='#0000FF'>return</font> "<font color='#CC0000'>bad_any_cast</font>"; <b>}</b>
    <b>}</b>;

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>class</font> <b><a name='any'></a>any</b>
    <b>{</b>
        <font color='#009900'>/*!
            INITIAL VALUE
                - is_empty() == true
                - for all T: contains&lt;T&gt;() == false

            WHAT THIS OBJECT REPRESENTS
                This object is basically a type-safe version of a void*.  In particular,
                it is a container which can contain only one object but the object may
                be of any type.  

                It is somewhat like the type_safe_union except you don't have to declare 
                the set of possible content types beforehand.  So in some sense this is 
                like a less type-strict version of the type_safe_union.
        !*/</font>

    <font color='#0000FF'>public</font>:

        <b><a name='any'></a>any</b><font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - this object is properly initialized
        !*/</font>

        <b><a name='any'></a>any</b> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> any<font color='#5555FF'>&amp;</font> item
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - copies the state of item into *this.  
                - Note that *this and item will contain independent copies of the
                  contents of item.  That is, this function performs a deep
                  copy and therefore does not result in *this containing
                  any kind of reference to item.
        !*/</font>

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font> <font color='#0000FF'>typename</font> T <font color='#5555FF'>&gt;</font>
        <b><a name='any'></a>any</b> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> T<font color='#5555FF'>&amp;</font> item
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - #contains&lt;T&gt;() == true
                - #cast_to&lt;T&gt;() == item
                  (i.e. a copy of item will be stored in *this)
        !*/</font>

        <font color='#0000FF'><u>void</u></font> <b><a name='clear'></a>clear</b> <font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - #*this will have its default value.  I.e. #is_empty() == true
        !*/</font>

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> T<font color='#5555FF'>&gt;</font>
        <font color='#0000FF'><u>bool</u></font> <b><a name='contains'></a>contains</b> <font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font> <font color='#0000FF'>const</font>;
        <font color='#009900'>/*!
            ensures
                - if (this object currently contains an object of type T) then
                    - returns true
                - else
                    - returns false
        !*/</font>

        <font color='#0000FF'><u>bool</u></font> <b><a name='is_empty'></a>is_empty</b><font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font> <font color='#0000FF'>const</font>;
        <font color='#009900'>/*!
            ensures
                - if (this object contains any kind of object) then
                    - returns false 
                - else
                    - returns true 
        !*/</font>

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> T<font color='#5555FF'>&gt;</font>
        T<font color='#5555FF'>&amp;</font> <b><a name='cast_to'></a>cast_to</b><font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - if (contains&lt;T&gt;() == true) then
                    - returns a non-const reference to the object contained within *this
                - else
                    - throws bad_any_cast
        !*/</font>

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> T<font color='#5555FF'>&gt;</font>
        <font color='#0000FF'>const</font> T<font color='#5555FF'>&amp;</font> <b><a name='cast_to'></a>cast_to</b><font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font> <font color='#0000FF'>const</font>;
        <font color='#009900'>/*!
            ensures
                - if (contains&lt;T&gt;() == true) then
                    - returns a const reference to the object contained within *this
                - else
                    - throws bad_any_cast
        !*/</font>

        <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font><font color='#0000FF'>typename</font> T<font color='#5555FF'>&gt;</font>
        T<font color='#5555FF'>&amp;</font> <b><a name='get'></a>get</b><font face='Lucida Console'>(</font>
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - #is_empty() == false
                - #contains&lt;T&gt;() == true
                - if (contains&lt;T&gt;() == true)
                    - returns a non-const reference to the object contained in *this.
                - else
                    - Constructs an object of type T inside *this
                    - Any previous object stored in this any object is destructed and its
                      state is lost.
                    - returns a non-const reference to the newly created T object.
        !*/</font>

        any<font color='#5555FF'>&amp;</font> <b><a name='operator'></a>operator</b><font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>
            <font color='#0000FF'>const</font> any<font color='#5555FF'>&amp;</font> item
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - copies the state of item into *this.  
                - Note that *this and item will contain independent copies of the
                  contents of item.  That is, this function performs a deep
                  copy and therefore does not result in *this containing
                  any kind of reference to item.
        !*/</font>

        <font color='#0000FF'><u>void</u></font> <b><a name='swap'></a>swap</b> <font face='Lucida Console'>(</font>
            any<font color='#5555FF'>&amp;</font> item
        <font face='Lucida Console'>)</font>;
        <font color='#009900'>/*!
            ensures
                - swaps *this and item
                - does not invalidate pointers or references to the object contained 
                  inside *this or item.  Moreover, a pointer or reference to the object in 
                  *this will now refer to the contents of #item and vice versa.
        !*/</font>

    <b>}</b>;

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>inline</font> <font color='#0000FF'><u>void</u></font> <b><a name='swap'></a>swap</b> <font face='Lucida Console'>(</font>
        any<font color='#5555FF'>&amp;</font> a,
        any<font color='#5555FF'>&amp;</font> b
    <font face='Lucida Console'>)</font> <b>{</b> a.<font color='#BB00BB'>swap</font><font face='Lucida Console'>(</font>b<font face='Lucida Console'>)</font>; <b>}</b>
    <font color='#009900'>/*!
        provides a global swap function
    !*/</font>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font>
        <font color='#0000FF'>typename</font> T
        <font color='#5555FF'>&gt;</font> 
    T<font color='#5555FF'>&amp;</font> <b><a name='any_cast'></a>any_cast</b><font face='Lucida Console'>(</font>
        any<font color='#5555FF'>&amp;</font> a
    <font face='Lucida Console'>)</font> <b>{</b> <font color='#0000FF'>return</font> a.cast_to<font color='#5555FF'>&lt;</font>T<font color='#5555FF'>&gt;</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; <b>}</b>
    <font color='#009900'>/*!
        ensures
            - returns a.cast_to&lt;T&gt;()
    !*/</font>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>template</font> <font color='#5555FF'>&lt;</font>
        <font color='#0000FF'>typename</font> T
        <font color='#5555FF'>&gt;</font> 
    <font color='#0000FF'>const</font> T<font color='#5555FF'>&amp;</font> <b><a name='any_cast'></a>any_cast</b><font face='Lucida Console'>(</font>
        <font color='#0000FF'>const</font> any<font color='#5555FF'>&amp;</font> a
    <font face='Lucida Console'>)</font> <b>{</b> <font color='#0000FF'>return</font> a.cast_to<font color='#5555FF'>&lt;</font>T<font color='#5555FF'>&gt;</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; <b>}</b>
    <font color='#009900'>/*!
        ensures
            - returns a.cast_to&lt;T&gt;()
    !*/</font>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
<b>}</b>

<font color='#0000FF'>#endif</font> <font color='#009900'>// DLIB_AnY_ABSTRACT_H_
</font>


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